Technical Abstract:
This report describes a field evaluation of advanced orange-fleshed sweetpotato genotypes from the USDA ARS sweetpotato breeding program at the U. S. Vegetable Laboratory (USVL), Charleston, SC in 2008. This field experiment included four insect-susceptible check cultivars (‘Beauregard’, ‘Diane’, ‘Hernandez’, and ‘SC1149 19’), three insect-resistant check cultivars (‘Charleston Scarlet’, ‘Regal’, and ‘Ruddy’), 79 advanced genotypes from this program, and four other varieties that were evaluated for insect resistance in field trials of four replications at the USVL. ANOVA indicated that there were highly significant entry effects for percent uninjured roots, WDS index (Wireworm, Diabrotica, Systena), percent sweetpotato weevil damaged (Cylas formicarius [F.]) roots, percent flea beetle damaged (Chaetocnema confinis Crotch) roots, and percent grub damaged (Plectris aliena Chapin and/or Phyllophaga spp.) roots. Sixty-eight sweetpotato genotypes had a significantly higher percentage of uninjured roots than the four susceptible check cultivars (‘Beauregard’, ‘Diane’, ‘Hernandez’, and ‘SC1149 19’). Seventy-six genotypes had a significantly lower WDS rating than the four susceptible checks. All but seven genotypes had significantly lower infestation by sweetpotato flea beetles than did ‘SC1149-19’ or ‘Hernandez’. Seventy-three genotypes had significantly lower percentage of infestation by grubs than did the four susceptible checks. The sweetpotato weevil infestation at the USVL in 2008 was very low; nevertheless, 68 genotypes had significantly lower percentage of infestation by SPW than did ‘SC1149-19’ or ‘Beauregard’.